I don't want to get attacked by the Venice lovers, but My experience in this city was not the best one, and I think people should see both good and bad travel stories before deciding to travel somewhere.
I spent 4 days in Venice. I enjoyed a walking tour from someone who lives there and absolutely loved watching the orchestra at the Florinian over lunch. Getting lost in Venice was not as romantic as people say though. Maybe it had to do with the time of year I visited (May) but the low traffic side streets were extremely dirty. There were dog droppings everywhere and I even came across one Alleyway with human excrement in it. I realize that graffiti is a common part of major Italian cities as well, but I also hated that there was graffitti everywhere. All of the low traffic areas that might otherwise have been very charming were ruined by spraypaint.
Venice is obviously a unique city, and I am glad to have seen it, but I honestly would not recommend it as a travel destination for any more than 1 night.